Aminoglycoside antibiotics are a useful class of antibiotics which include the streptomicins, kanamycins, neomycins, gentamicins, tobramycins, amikacin, and the more recently discovered fortimicins. It is known that the antibacterial and pharmacological properties of many of the naturally produced aminoglycoside antibiotics can be advantageously altered by structural modifications. For example, certain chemical modifications in the gentamicin and kanamycin family of antibiotics provide compounds which are either less toxic than the parent antibiotic or are intrinsicly more active either by virtue of an altered antibiotic spectum of by virtue of an increased activity against resistant strains or an increase in the basic acitivy of the naturally produced antibiotic.
Chemical modification has also been found to be of value in the fortimicin family of antibiotics. Modifications producing the most active derivatives of fortimicin A are the modifications providing the 2-deoxyfortimicins disclosed in commonly assigned U.S. Pat. Nos. 4,192,867 and 4,187,297 and the 3-O-demthylfortimicins disclosed in U.S. Pat. No. 4,124,756, issued Nov. 7, 1978.
While highly active fortimicin derivatives have already been provided, because of the resistance problem rapidly encountered with aminoglycoside therapy, there is a need for improved entities or entities which exhibit comparable antibacterial spectra but which can be held in reserve in the event that current therapy becomes of less value because of the development of resistant organisms. The present invention provides one class of fortimicins which fullfill the above need.